Converting Old Steam Pipe to Natural Gas?

Guest,

Back then, the joints certainly were not sealed with any type of teflon tape. Possibly red lead or white lead. Black iron pipe was and is suitable for gas service. In terms of corrosion, the only problems the gas will introduce is the odor-producing additive contains sulfur. I assume you have already done a good job of ensuring there are no sections of copper or galvanized pipe present in the riser(s).

Two suggestions: 1) Discuss this with the local code officials. Surely, you are doing this with permits and inspections! If there are any code problems they will help you with avoiding them. 2) Do a pressure test of the riser, just as if it were a new gas line being put into use. This would be required after all piping is connected, so this extra test now will give you confidence that the rest of the work isn't for nothing. The pressure test may reveal many small leaks at joints on the riser. If so, you may have to take it apart at the joints, apply new compound and put it back together.

--JMM

Hello,

Some of the pipe may be usable as as conduit to insert the gas pipe through. We do it quite frequently when upgrading underground systems with smaller diameter pipe with higher delivery pressures

Rustyh20 has a very good suggestion. The liklihood of the gas inspector passing the old sections without provisions for at least a visual inspection are slim to none. Use the pipe as a conduit for flexible gas piping to provide support and access.

I can guarantee two things for you:-

1) there is legislation that demands different sealing methods and pipe type

2) If you did use it, you would have leaks all over the place and there may be corrosion in places you cannot get at!!!

Don't even dream about doing it!!!

I would remind you of the old German saying:-

"He saves money, no matter what it costs!"

Good afternoon, Guest. How many stories is your office building? What is the diameter of the old steam pipe? What was the steam pressure? I would venture to say your local authorities would make you jump thru a lot of hoops before they'd approve it, even if it were in good shape. They'd make you assume total liability. It'd probably be more productive to see if it could be used as a sleeve thru which you'd insert modern approved gas pipe. What does your local gas utility say? Depending on your P1, P2, Q, and pipe diameter, you may be able to insert a properly-sized gas pipe to your benefit. Assuming the numbers calc out, your local gas utility sales represtentative may be able to coordinate a P1 to accomodate your design. I think you should consult a local mechanical or gas engineer. If your local gas utility were inclined to help with the design, that'd be great.

Thanks all.

I Think the most compelling argument relates to 1.) antiquated methods of sealing joints 2.) Unlikelihood of code passage.

We actually did thread both ends, cap and pressure test at 80 PSI overnight with no problems, so I'm quite sure it would work, I just don't think our inspector would go for it, and don't really know what the long-term consequence of running gas (albeit at 10PSI or less) through it instead of steam would be.

Although the conduit idea is a good one, it won't work in this case because this riser is the exact size (4" internal diameter) that our plumbing engineer says we need. So no room for error.

Sigh...Time to get out the core drill!

Thanks again.

Rich

Guest,

It won't hurt to talk with the inspector, however. Code officials usually are happy to be consulted and have their opinion heard and respected. They may have had a similar situation in the past and have some experience (either positive or negative) to share. Also, unless you are adding pressure reduction in the lines, normal gas pressure for the consumers is much less than 10 psi.

--JMM

If you are running 10 psi or even less that is a lot of gas flow. What have you considered for insertion piping. Possibly copper because of it flex capabilities. I dont really know how code works for poly pipe when inserted indoors. Plastic to steel transitions are available and can be put at junctions or joints. the steel portion can be either welded or threaded. I really dont know what the configuration looks like. I wish you the best in this project.